Percentage in Pounds

cassie00

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Ok, this may be a very simple math problem that I'm just missing a step to, but whatever.

I have a bag of feed, and I'm trying to figure out what exactly I need to add to it to supplement anything my animals may need that they're not getting enough of. The protein, fiber, salt, calcium, etc. are all in percentages. It's a 50 lb bag. We'll use the calcium. In my bag of feed, the calcium content is about 1.10%. One of my animals needs about 2 pounds of calcium a day. How do I determine how much calcium (in poundage) is in my bag so I can supplement the rest of the calcium they need or switch feeds.

P.S. - I tried turning all the percentages into decimals and multiplying them by 50, but when I added the numbers together they were greater than 50.
 

lev888

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50lb * 1.10/100
If you do this for each ingredient and total you should get 50lb. Try setting up a spreadsheet to avoid mistakes in calculations.
 

cassie00

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It added up to around 53
 

cassie00

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Also, when I add up the mineral % in a 50 lb block, the sums added up to 66 (rounded)
 

tkhunny

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It added up to around 53
Hmmm... Not really much to do about that, other than:

1) Check your work VERY CAREFULLY. The spreadsheet is a good idea. Some rounding might be expected, but not a 6% error.
2) Complain to whatever governing body has authority over such bag labeling. AAFCO?
3) It is possible that only some of the ingredients are reported in percentages. Others might be PPM or IU/lb or etc. This would confuse the issue a bit, but it still would not lead to an OVERstatement of the total.
 
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tkhunny

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Also, when I add up the mineral % in a 50 lb block, the sums added up to 66 (rounded)
You're going to have to provide a picture of this label, I think.
 

cassie00

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The one with red in it is the salt block, the other is the bag. I didn't even add the ppm or IU/lb units to the 53 sum. I averaged the ones with the min. and max. percentages.
 

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tkhunny

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That first one gives us a clue. They are only guessing at the actual percentages. Minimum and Maximum are given. This is not a precisely controlled process.

The second one, the one we are really talking about, gives various percentages that add up to more than 100%. That should strike you as a bit odd. However, each ingredient has another indication, either "min" or "max". "min" means there is AT LEAST the given percentage in the mix. "max" means there is AT MOST the given percentage in the mix. It's not perfectly clear to me how to adjust for this except to say that if the manufacturer doesn't know how much of each ingredient is in the mix, how can you expect to calculate it?! If it were me, I would just scale it. Do whatever correct thing you already did - the one that came to around 53 - and divide everything by 1.0575. That should get you close.

The third is as I predicted - multiple types of measurements. PPM is okay, since that's just like a percentage. 1% = 1 PPH or 1 Part per hundred. 1 PPM is just 1 part per Million and would be difficult or relatively useless to report as a percentage compared to such large values as 1.5%. It may be difficult to imagine that 1.5% is the LARGE number in this scenario.

85 PPM = 85 parts per 1,000,000
8.5 parts per 100,000
0.85 parts per 10,000
0.085 parts per 1,000
0.0085 parts per 100 = 0.0085% - It's a pretty small piece.

I'm afraid that's the good news. IU/lb doesn't have that kind of conversion.
 
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